<p>Symmetry plays a significant role in protein structural assembly and
function. This is especially true for large homo-oligomeric protein complexes
due to stability and finite control of function. But, symmetry in proteins are
not perfect due to unknown reasons and leads to pseudosymmetry. This study
focuses on symmetry analysis of homo-oligomers, specifically homo-dimers,
homo-trimers and homo-tetramers.</p>
<p>We
defined Off Symmetry (OS) to measure the overall symmetry of the protein and
Structural Index (SI) to quantify the structural difference and Assembly Index
(AI) to quantify the assembly difference between the subunits. In most of the
symmetrical homo-trimer and homo-tetramer proteins, Assembly Index contributes
more to Off Symmetry and in the case of homo-dimer, Structural index
contributes more than the Assembly Index. The main chain atom Carbon-Alpha (CA)
is more symmetrical than the first side chain atom Carbon-Beta (CB), suggesting
protein mobility may contribute to the pseudosymmetry. In addition, Pearson
coefficient correlation between their Off-Symmetry and their respective atoms
B-Factor (temperature factor) are calculated. We found that the individual
residues of a protein in all the subunits are correlated to their average
B-Factor of these residues. The correlation with BFactor is stronger in
Structure Index than Assembly Index. All these results suggest that protein
dynamics play an important role and therefore a larger off-symmetry may
indicate a more mobile and flexible protein complex.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7430249 |
| Date | 16 January 2020 |
| Creators | Catherine Jenifer Rajam Rajendran (5931113) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Analysis_of_Pseudo-Symmetry_in_Protein_Homo-Oligomers/7430249 |
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